Infants born prematurely (<37 weeks gestation) experience delayed growth and sub-optimal bone mineralization that continues into childhood. Long-term effects of delayed bone mineralization include shorter stature and a higher rate of fracture than full term peers. Evidence suggests that Developmental Massage Therapy (DMT) that includes massage and kinesthetic movement may promote bone mineralization and improve postnatal growth. The purpose of this study is to provide career training and identify the response associated with DMT treatment on bone growth in preterm infants. This research will examine three specific aims to identify the 1) effects of DMT on bone mineral content and bone strength 2) effects of DMT on biomarkers for bone formation/resorption and their relationship with measures of bone mineralization and strength in Specific Aim 1, and 3) relationship of DMT with the levels and bioavailability of Insulin like growth factor (IGF1). We predict that infant DMT will result in improved bone mineral content (DEXA) and bone strength (tibia speed of sound), greater levels of bone formation biomarkers (osteocalcin & bone specific alkaline phosphotase) and lower levels of bone resorption markers (urinary pyridinium crosslink) in association with increased bone density and strength, and alterations of IGF1 binding proteins in the IGF1 axis that increase IGF1 bioavailability. This clinical study has a prospective, blinded, longitudinal design. Premature infants between 29 4/7 and 32 3/7 weeks gestation are randomized to either daily DMT or control treatments. DMT consisted of massage therapy with kinesthetic movement twice daily while the infant is in the NICU. Control treatment includes everything but DMT. Weekly measurements during intervention are taken at multiple time points during a period of accelerated postnatal maturation, growth, and development. The longitudinal design provides a stronger understanding of the modulating effects of DMT on postnatal growth and bone mineralization in premature infants and increases the statistical power of the analysis. PUBLIC HEALTH RELEVANCE: Infants born prematurely (<37 weeks gestation) experience delayed growth and sub-optimal bone mineralization that continues into childhood. Additional long-term effects of delayed bone mineralization include shorter stature and a higher rate of fracture than full term peers. Evidence suggests that developmental massage therapy (DMT) that includes massage and kinesthetic movement may promote bone mineralization and postnatal growth.